Building expansion joints

[ntattose]

We are beginning design on a large warehouse structure. Tilt up walls with metal deck over bar joist roof. I have the Vulcraf tech guide 65 on expansion joints. Is this the best resource? What are some of you folks using for spacing between expansion joints?

 

[OldDawgNewTricks]

Well, that's not a "Vulcraft" document. It's the Federal Construction Council's 1974 report. But yes, it is what most people use.

 

[Joe_bode]

Hello,

I have a building design on partly basement structure and the rest of the building is on grade, all having isolated footing. Is it a must to introduce a separation joint on the vertical line where the basement covers from the rest of the building? Note that the soil is very stable kpa of about 200kN/m2

 

[driftLimiter]

You might consider using a sidelap connection that is ductile so that expansion joints aren't required. I recently learned of these in the Verco Roof Structure Design Manual
Its a really nice detailed guide of each element's considerations and design for metal deck roof systems.

[link]https://vercodeck.com/wp-content/uploads/2021/04/Roof_Deck_Design_Guide_V2021.pdf[/url]

 

[ntattose]

Driftlimiter
Great reference. Thanks

 

[Joe_bode]

Thank you for your prompt response @driftlimiter. I want to further confirm if the the sidelap is applicable to concrete buildings. I have attached a sketch to show how the building looks like. Note: 1. Roof Level, 2. Upper level, 3. Ground level and 4, Basement level. 5 is the retaining wall. I believe having the footings at different levels may not pose problems, but how does the sidelap help as oppose to introducing joints along vertical line of the retaining wall.

 

[driftLimiter]

The sidelap connection only relives thermal stresses in the roof structure I was actually answering the OP's post. You would need to address other elements separately. The partial basement question is a good one, you kind of have different stiffness of your walls in plane that needs to be reckoned with, as far as putting a joint there, I would need to understand more about the building to offer any recommendations on that.

 

[OldDawgNewTricks]

driftLimiter, thanks for the link. I have that catalog, but I had not read that specific portion before. It does bring to mind a couple of question though:
1. The word "ductile" implies that the diaphragm could yield just from thermal effects. Is that a good idea? Is there any reduction for seismic loads if the diaphragm connections have already yielded before the seismic event starts?
2. The catalog shows a couple of examples where their system was used to achieve over 1200 foot long buildings with no expansion joints so it must be possible. But surely there is more to it than just using their diaphragm connections. What about the rest of the structure? It would need to go through the same differential movements too, right?

 

[driftLimiter]

@OldDawgNewTricks

To be honest, I haven't had to deal with such a large building and thermal expansion issues in detail yet. I believe Verco was saying they have tested the 'ductility' of their connection for thermal effects. I hear what your saying about strength loss due to yielding from thermal I would defer to Verco with that question . Reg'd the rest of the structure, I guess we would need to better understand how the roof resists the thermal effects, perhaps each sidelap connection is 'taking-up' the displacement and it isn't getting passed to the exterior walls.

 

[Joe_bode]

thanks @driftlimiter for taking time to address my question, i need to know what more you require to know about the building. i have attached more drawings for better view. thanks